1. Field of the Invention
The present invention pertains to an apparatus for limiting the oscillation amplitudes of suspension elements and compensation elements of elevators, preferably of an elevator utilizing a counterweight travelling in guides.
2. Discussion of the Background of the Invention and Material Information
In elevators with great lifting heights, the suspension elements and compensation elements have the tendency to oscillate in the horizontal direction. The stimulus of these oscillations has different causes, with the operation of the elevators itself being one of the main causes. During periodic accelerations, moving at high velocity and retardation, due to small deviations in the vertical plane of the guide rails, small horizontal movement components are produced by the elevator car and the counterweight. These horizontal movement components incite horizontal oscillations in the suspension and compensation elements, with the extent of these oscillations, in the self-resonant frequency region of these elements, being so large that mutual contact, as well as contact with elevator shaft apparatus occurs, which lead to damage of the installation apparatuses and interruptions of elevator operation.
The prior art includes differing apparatuses which are alleged to prevent the formation of such oscillations. U.S. Pat. No. 4,117,908 discloses a corresponding apparatus comprised of an oscillation suppressor or damper, located below the motor room ceiling in the elevator shaft and a further suppressor on the elevator car. These are constructed as a frame-like structure and include stops or buffers that are positioned closely to the suspension cables and have a greater or lesser spacing relative to the upper portion of the elevator car or the ceiling of the motor room. Upon the occurrence of cable oscillations, for example as a result of earthquakes, these oscillations are kept away from the elevator car and the elevator driving mechanism, but are not particularly limited themselves.
U.S. Pat. No. 3,666,051 discloses a further apparatus wherein cable guides, which travel with the elevator car during downward travel of the elevator car, are deposited at predetermined distances relative to each other, by means of stops or buffers at the guide rails and which during upward travel of the elevator car are again retrieved. This apparatus is designed for external elevator systems that are exposed to strong wind influences. This principle is too expensive for use in internal building installations and additionally no high velocities can be realized since the deposition and collection of the cable stabilizers causes knocking noises in the elevator car.
In the two previously-noted examples, the oscillation suppression or damping is occasioned on the elevator car side of the installation. The consideration or basis of the present invention however resides in the fact that greater oscillation movements are required on the elevator car side than on the counterweight side of the installation until the suspension and/or the compensation elements strike against a fixed or a movable installation part.
Therefore, it is the task or object of this invention, to produce an apparatus for limiting the oscillation amplitudes of suspension and compensation means on the counterweight side of the elevator installation that are simple and inexpensive as well as prohibit the contact of the suspension and/or compensation means with installation parts and which provide additional safety during extreme deflections.